Nothing Special / mbed-STM32F103C8

Modification of Mbed-dev library for LQFP48 package microcontrollers: STM32F103C8 (STM32F103C8T6) and STM32F103CB (STM32F103CBT6) (Bluepill boards, Maple mini etc. )

Fork of mbed-STM32F103C8_org by Nothing Special

Library for STM32F103C8 (Bluepill boards etc.).
Use this instead of mbed library.
This library allows the size of the code in the FLASH up to 128kB. Therefore, code also runs on microcontrollers STM32F103CB (eg. Maple mini).
But in the case of STM32F103C8, check the size of the resulting code would not exceed 64kB.

To compile a program with this library, use NUCLEO-F103RB as the target name. !

Changes:

  • Corrected initialization of the HSE + crystal clock (mbed permanent bug), allowing the use of on-board xtal (8MHz).(1)
  • Additionally, it also set USB clock (48Mhz).(2)
  • Definitions of pins and peripherals adjusted to LQFP48 case.
  • Board led LED1 is now PC_13 (3)
  • USER_BUTTON is now PC_14 (4)

    Now the library is complete rebuilt based on mbed-dev v160 (and not yet fully tested).

notes
(1) - In case 8MHz xtal on board, CPU frequency is 72MHz. Without xtal is 64MHz.
(2) - Using the USB interface is only possible if STM32 is clocking by on-board 8MHz xtal or external clock signal 8MHz on the OSC_IN pin.
(3) - On Bluepill board led operation is reversed, i.e. 0 - led on, 1 - led off.
(4) - Bluepill board has no real user button

Information

After export to SW4STM (AC6):

  • add line #include "mbed_config.h" in files Serial.h and RawSerial.h
  • in project properties change Optimisation Level to Optimise for size (-Os)

drivers/I2C.cpp

Committer:
mega64
Date:
2017-04-27
Revision:
148:8b0b02bf146f
Parent:
146:03e976389d16

File content as of revision 148:8b0b02bf146f:

/* mbed Microcontroller Library
 * Copyright (c) 2006-2015 ARM Limited
 *
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *
 *     http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */
#include "drivers/I2C.h"

#if DEVICE_I2C

namespace mbed {

I2C *I2C::_owner = NULL;
SingletonPtr<PlatformMutex> I2C::_mutex;

I2C::I2C(PinName sda, PinName scl) :
#if DEVICE_I2C_ASYNCH
                                     _irq(this), _usage(DMA_USAGE_NEVER),
#endif
                                      _i2c(), _hz(100000) {
    // No lock needed in the constructor

    // The init function also set the frequency to 100000
    i2c_init(&_i2c, sda, scl);

    // Used to avoid unnecessary frequency updates
    _owner = this;
}

void I2C::frequency(int hz) {
    lock();
    _hz = hz;

    // We want to update the frequency even if we are already the bus owners
    i2c_frequency(&_i2c, _hz);

    // Updating the frequency of the bus we become the owners of it
    _owner = this;
    unlock();
}

void I2C::aquire() {
    lock();
    if (_owner != this) {
        i2c_frequency(&_i2c, _hz);
        _owner = this;
    }
    unlock();
}

// write - Master Transmitter Mode
int I2C::write(int address, const char* data, int length, bool repeated) {
    lock();
    aquire();

    int stop = (repeated) ? 0 : 1;
    int written = i2c_write(&_i2c, address, data, length, stop);

    unlock();
    return length != written;
}

int I2C::write(int data) {
    lock();
    int ret = i2c_byte_write(&_i2c, data);
    unlock();
    return ret;
}

// read - Master Reciever Mode
int I2C::read(int address, char* data, int length, bool repeated) {
    lock();
    aquire();

    int stop = (repeated) ? 0 : 1;
    int read = i2c_read(&_i2c, address, data, length, stop);

    unlock();
    return length != read;
}

int I2C::read(int ack) {
    lock();
    int ret;
    if (ack) {
        ret = i2c_byte_read(&_i2c, 0);
    } else {
        ret = i2c_byte_read(&_i2c, 1);
    }
    unlock();
    return ret;
}

void I2C::start(void) {
    lock();
    i2c_start(&_i2c);
    unlock();
}

void I2C::stop(void) {
    lock();
    i2c_stop(&_i2c);
    unlock();
}

void I2C::lock() {
    _mutex->lock();
}

void I2C::unlock() {
    _mutex->unlock();
}

#if DEVICE_I2C_ASYNCH

int I2C::transfer(int address, const char *tx_buffer, int tx_length, char *rx_buffer, int rx_length, const event_callback_t& callback, int event, bool repeated)
{
    lock();
    if (i2c_active(&_i2c)) {
        unlock();
        return -1; // transaction ongoing
    }
    aquire();

    _callback = callback;
    int stop = (repeated) ? 0 : 1;
    _irq.callback(&I2C::irq_handler_asynch);
    i2c_transfer_asynch(&_i2c, (void *)tx_buffer, tx_length, (void *)rx_buffer, rx_length, address, stop, _irq.entry(), event, _usage);
    unlock();
    return 0;
}

void I2C::abort_transfer(void)
{
    lock();
    i2c_abort_asynch(&_i2c);
    unlock();
}

void I2C::irq_handler_asynch(void)
{
    int event = i2c_irq_handler_asynch(&_i2c);
    if (_callback && event) {
        _callback.call(event);
    }

}


#endif

} // namespace mbed

#endif